Many years ago when I was in college my summer job for the last 2 years was driving around at night spraying for mosquitoes. They had a fleet of trucks, and we'd usually drive 100 - 200 miles every night between driving to the different towns and then spraying once we got there. We trained someone from the WHO one year so they could do the same in Africa as well as sprayed for many of the towns in the Chicago burbs in addition to the helicopter and day crew people who drove around spreading larvacide - this was a big operation at the time. The increase in mosquitoes this year got me thinking about this company again, and when I looked up this company on the the interwebs I found they don't spray anymore. But they still spread the larvacide during the day and use bicycles to do this. That's quite a change from when I worked there, they must have had a good reason for the change.